Peeling machines are known, which comprise feed means, suitable to axially feed each product to be worked along a longitudinal axis, and a rotating head which is provided with a through central cavity in which, during use, the product to be worked is made to pass.
The rotating head is made to rotate with respect to a fixed support, coaxially to the longitudinal axis, by means of first drive means.
The tools are installed on the rotating head and are associated with corresponding adjustment devices which each comprise a slider, radially mobile with respect to the longitudinal axis and on which one of the tools is installed.
Each adjustment device also comprises a wedge-type hub connected to the slider that supports the tool.
The wedge-type hub can be moved in a direction parallel to the longitudinal axis by the action of screwing, in one direction or the other, a calibrated screw disposed with its axis of rotation substantially parallel to the longitudinal axis, and which screws onto/from the wedge-type hub.
The calibrated screw is selectively driven by second drive means.
Control means and a kinematic-differential unit are interposed between the second drive means and the calibrated screw to determine the selective and simultaneous activation of the latter, and to perform the micrometric adjustment of the radial position of the tools, also while the rotating head is rotating.
In particular, a rotation of the second drive means is transmitted to the calibrated screw by an array of toothed wheels to make the calibrated screw rotate in one direction or the other, thus moving the wedge-type hub, and in turn the sliders and corresponding tools, with a consequent variation in the diameter of the product.
The presence of a wedge-type hub to determine the radial movement of the tools greatly limits the radial travel to which they can be subjected. Indeed, high radial travels of the tools would entail a considerable increase in the bulk of the rotating heads.
Furthermore, the known peeling machine described above, given its configuration, can be used only for limited ranges of size of the oblong product to be worked, dictated by the particular sizes of the rotating head. If it is necessary to process oblong products with very different values of size, the rotating head must be replaced depending on the sizes of the oblong product to be processed.
A peeling machine is also known, from DE-A-10.2009.041.340, which comprises a rotating head on which a plurality of tools are installed. The rotating head is made to rotate by a first motor connected to the rotating head by a pinion and a toothed crown installed on the head.
The tools are installed mobile radially with respect to the working axis of the machine. The radial movement of each tool is commanded by a plurality of toothed elements made to rotate simultaneously by a toothed crown. The toothed crown is installed on the rotating head and a second motor acts upon it, configured to make the toothed crown rotate and in this way to adjust the position of the tools. To keep the tools in a fixed radial position with respect to the rotating head, the second motor has to be driven with a speed of rotation that is a function of the speed of rotation of the first motor. However, this solution requires a control of the speed of rotation of the first motor and the second motor that are difficult to obtain precisely.
Furthermore, this solution requires that, during the peeling of a metal product, the second motor that adjusts the position of the tools is driven to prevent any loss of positioning of the tools from occurring.
The known solutions described above are also particularly complex to achieve and present considerable difficulties in calibrating the tools because of the large number of components and the mechanical plays between them, which make the peeling machine not very precise.
Document JP-A-2011-020216 describes a turning machine in which the product to be worked is kept in a fixed position by vises while the cutting head is moved linearly along linear guides in order to perform the turning.
However, turning machines are very different in construction from peeling machines and are therefore not suitable for performing peeling operations on tubular products.
Merely by way of example, a turning machine does not allow to work very long tubular products because it is not possible to pass the material through the machine.
Moreover, in the solution shown in JP-A-2011-020216, the adjustment system is positioned on the side opposite the cutting head and the adjustment action is transmitted through a hollow shaft installed coaxially to the axis of the machine and the product to be worked is made to pass through at least part of this. The sizes of the hollow shaft limit the maximum sizes of the metal product to be worked. Furthermore, in the solution shown in JP-A-2011-020216, the adjustment system consists of a harmonic reducer or an epicycloid differential which takes the motion from the main motor by means of suitable reduction gears that also invert the direction of rotation. This solution is particularly complex given the large number of toothed components which not only increase the cost of the machine but also result in a system that is less rigid and hence less precise.
There is therefore a need to perfect a peeling machine for oblong products that can overcome at least one of the disadvantages of the state of the art.
In particular, one purpose of the invention is to obtain a peeling machine which is simple to make and compact.
Another purpose of the present invention is to obtain a peeling machine which is extremely versatile and can be used for different ranges of size.
Another purpose of the present invention is to obtain a peeling machine that is more efficient and precise compared with known solutions.
Another purpose of the present invention is to obtain a peeling machine that allows to adjust the position of the tools also during the normal functioning of the peeling machine in order to obtain a product with different diameters.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.